Suspension system for vehicles



o@ 8, 1940- w. E. VAN DoRN 2,217,033y

SUSPENSION sYs'rEu Foa VEHICLES Filed Nov. '7, '1939 3 Shee'ts-Sheet l.

f W. E. VAN DORN SUSPENSION SYSTEM FOR VEHICLES 5 Sheets-Sheet 2 Filed Nov. '7, 1939 TF .y W d. 5 W o fm W Oct. 8, 1940. w EqvAN DORN I 2,217,033

www@ f Patented Oct. 8, 1940 UNITED STATES PATENT oEFicE l 2,217.033 .Y sUsPENsIoN SYSTEM FoavEmoLEs William E. Van Dorn, Los Angeles, Calif., assignor to Pacific Railway Equipment Company, Los Angeles, Calif., a corporation of California y I Application November "I, 193.9, Serial No. 303,231 v 13 Claims. (Cl. 10s-453) This invention relates to suspension system for vehicles.

" 1 to varoius, types lof vehicles, and although it has j been specifically designed for application to rail- 5. way vehicles and will therefore be Illustratively v described as applied tothem, the invention isnot `uses. one for the suspensionand control of vehilfor suspension, controlanddraft connection of :articulated vehicle bodies.

fThis .present application and its appended claims are directed to the system of suspension 5 'and control of general adaptation regardless of articulation. v Mycopencling@application entitled Suspensionsystem for vehicles; filed on even date Y. herewithandbe'aring Ser. No.' 303,232,` and the vclaixnstherein,- are directed to'the system of suspension and control -for V articulated vehicles. 'I'he v present application is a continuation in part of trolled oscillatory motion about a high level lonf gitudinal axis, rather thanthe tilting or rolling motion to `which present date vehicle bodies are subjected when subject to lateral forces; and, in

general,v givestov such a vehicle body controlled motions and freedoms'that result in higher safety and increasedV passenger comfort, `,and 1 therefore 40 enables higher speed to be attained even on present lday road beds and within the present reguf llations and restrictions applied to railway rolling stock. Y My invention provides for hanging the vehicle -45 body at a relatively lowlevel and with a relatively low center of gravity.- `And also, by the nature and action of its load-taking elements, and by its provision of lateral restraint applied to the body at a high level, it provides for oscillatory swinging of the body about a high longitudinal axis above the center of gravity. This last mentioned provision causes the body to swing pendulously -when subjected to any lateral thrusts, such as the lateral thrusts due to misalinement of trackage or centrifugal thrusts in The invention is generally applicablel limited to that particular :application and use.-v :The invention has two'further adaptations and 41,0 cle bodies regardless of articulation, and the other rounding curves. The motion of the bodyunder- I such thrusts is one of banking rather than that of tilting or rolling. f K i In its preferred forni, as herein described, the

suspension and control system involves a set or 5 unit of two laterally spaced supporting and controlling elements each mounted below upon the truck or wheel unit without the intervention of any bolster frame or central support in the na- These two supporting and conture of a swivel. trolling elements are spaced laterally from each other at opposite sides of, and symmetrically with respect to,l the longitudinal center of the truck and body. They extend upwardly from the truck or wheel unit, being more or less columnar in nature, and are supportingly and controllingly connected with the body, or 'some rigid portion of the body, through flexible or articulative parts located at a level above substantiallyV the level of .the body center of gravity. Each of these ele- 2 ments includes a member having a vertically elastic or vertically yielding action by which'the loadof the body is sprung and by which the body is Agiven the .oscillatory freedom necessary for its swinging banking action. And each of these elements also includes articulated members which, connecting `with the body at the high level, restrict or restrain lateral translative motion of .the body at that high level and consequently flx a high level swingingaxis for the body.

'Ihe articulate members which have just been spoken of also include suspension and body guiding and control members which also provide for the horizontal swivelling motion of the body with relation Ato the truck for wheel and axle unit.

These articulate members, specifically illustrated in the form of pairs of horizontally swinging links or arms, give thebody a'virtual swivelling center which may be longitudinally removed from the points of suspension.

draft betweenthe bodies is exclusively transmitted through the truck. And preferably the arrangement inv that case is such that the two ad jacent bodies, mounted on a single truck, have'45 draft connection which is arranged at the relatively low level of the truck or wheel unit and well below thelevelat which the bodies are suspended upon the truck. This draft connection,

preferably and illustratively in the form of a longitudinal draft bar, is freely flexible in all directions except longitudinally. In a longitudinal When the vehicle bodies 40 are articulated through a common truck the l direction it has some yieldability, for the absorption of longitudinal shocks; but its structure and action are such that the draft forces which are transmitted through the truck at a low level are transmitted between the truck and the car bodies exclusively through the low level draft connections, and not through the high level suspension and control connections to the body.

Further objects and the corresponding features and accomplishments of the invention will be un derstood from the following detailed and specific description of illustrative embodiments, reference for the purpose being had to the accompanyingl drawings, in which:

Fig. 1 is a fragmentary side view, partly in ele`- vation and partly in section on line I-I of Fig.

2, showing my suspension control system typi- `cally applied;

; axis;

Fig. 6 is a crossisection showing a modified v construction; and

Fig. 7 is a cross section of the form shown in Fig. 6 and illustrating the swinging or banking action of that form.

In the drawings in Fig. 1 I have illustrated two vehicle bodies A and B, suspended on two truck units which are designated generally in Fig. 1 as C and D. Each of these truck units C and D comprises two wheel and axle units III;

and the vehicle body A is illustrated as being supported at one end upon both the axle units I0 of truck unit C; while the truck unit D has one of its wheel and axle units I0 supporting an end of vehicle body A and its other wheel and axle unit III supporting the adjacent 'articulated end of vehicle body B. The two truck units C and DA and their body suspending and controlling devices are the same. Particular description will be given for the one that suspends both car bodies.

As illustrated here, each wheel and axle unit comprises a pair of wheels II, each wheel being set on a stub axle I2 which is suitably journaled at I3 and I4 in an axle frame I5 of the drop or U type. Mounted upon each axle frame I5 there are two upwardly reaching and laterally spaced columnar structures I6 which include upper heads I1 that are vertically movable. These upper heads I1 carry one member I8 of a universal joint, here shown as a ball-andsocketjoint; and the other member I9 of the joint is carried` by the free' end of a pivoted link arm 20. These pivoted arms are connected with and mounted upon a rigid kportion of the respective car body, `as for instance upon a structural cross partition 2|. The arms 20 lie in a substantially horizontal plane and are of the general nature of cranks, being connected with theicar body through their vertical pivotal shafts 22 being mounted in journalsk 23 which are rigidly attached .io the structural partitions 2I. -.'I'he arms 20 'are thus mounted so that they may swing about `vertical axes in a horizontal plane with reference to the car body. And the general arrangementis'such that in their normal positions the two link arms "of each pair' converge, when viewed in plan, toward a point which is located in the longitudinal central plane of the car body and lon'gitudinallyre-- swivelling axis longitudinally from the support-- ing elements.

Each columnar structure I6 is here shown as including two vertical longitudinally spaced telescopic spring columns 3|. In Fig. 4 ythese spring columns are shown as comprising vertically movable plungers 32 which are vertically guided in the portions 33 of frame I5, and which are directly attached to and support heads I1. Springs The general function of 34 are contained within the telescopic column thus formed and support plungers 32 and-head I1 and thus elastically' support the weight of the car body through the articulation formed by theuniversal joints I8, I3 and the swinging arms 20.

In the form of suspension shown in Fig. 4 the lower ends of springs 34 are supported in cups 35, and opposite spring-supporting cups are supported on the opposite ends of a late ral equalizing lever 36 which is centrally pivoted-on thev pivot pin `31 or 31a mountedin frame I5. By reference to Fig. 1 it will be seen that one of these levers 36 is mounted upon a short central longitudinal stud pin 31, while the stud pin 31a which carries the other lever 36 is screw-threaded at 31b into frame I5, so as to be securely longitudinally connected with-the frame and at the same time tobe rotative about' a longitudinal axis, for purposes which will appear.

Associated with each columnar structure I5 there is preferably a dash-pot which comprises a cylinder 40 and a piston 4I whose rod 42 is directly attached to the column structure head I1. The details of this dash-pot structure need not be described as they are well known. The

purpose and function is to retard and damp the vertical movements and vertical oscillations of the columnar structures and the 'car bodies.

The mounting of frame I5 upon its respective wheels may be throughthe medium of any suitable mounting arrangement. In the -present illustration the frame is shown as carrying the axle bearings directly, without the' interposition of any means allowing relative movements or means for absorbing shocks. Each head I1 carries a rubber or similar pad upon which the universal joint element I8 is carried, for the purpose of shock absorption, and allowance for errors of misalinement.

As shown in Figs. 1, 2 and 3, the two axle frames I5 of each truck are interconnected by a pair of longitudinally extending and laterally spaced connector links 45 whoseopposite ends are connected to the axle frames I5 by the horizontal pivot pins '41. By removing these pins the two wheel and axle units may be separated and the two adjacent cars thereby be disconnected. Each of these links 45 contains a screwtime the two axle frames may tilt relative to each other, and to the respective car body or bodies,

in longitudinal plane, and also may twist about a longitudinal axis relative to each other in orde to properly follow uneven trackage.

The columnar structures I6 reach up above the axle frames and into the car bodies to such an elevation that the level L of the two articulate ball joints I8, I9, is preferably well above the body center of gravity, which is indicated C. G. in the drawings. This is for the purpose of suspending the body for lateral swinging oscillation about a longitudinal center above substantially the level of center of gravity, and for the purpose of applying to` the body, at that high level, a restrain on its lateral motion which will force the body to oscillate about that high center of oscillation. But this suspension and 4control connection to the body at that high level porting columnar structures are longitudinally tiltable with reference to the body and the truck and consequently allow relative longitudinal freedom to the body.

hLongitudinal draft connection between the trucks. or the wheel and axle units. and the respective body or bodies, is here illustrated as being made exclusively at a relatively low level; at

substantially the level of the axle frames or of the axles themselves, and well belowfthe level of suspension and control connection to the body. Thus each wheel and axle unit. or axle frame. is connected to its respective body bv a low level longitudinal draw bar 50. The body end of this draw bar is connected by the vertical loose pivot 5I with the yielding or spring device 52 which is mounted on the under side of the body frame. And the truck end of each draw bar is shown as connected through the universal joint 53 with the outer end of the swivelling pivot stud 31a.

' The spring device 52 is of the ordinary and well- As I have noted before. Fig. l shows the truck D in an arrangement where it performs the function of articulation between the two car bodies A and B. In Figs. l, 2 and 3, these two car bodies A and B are shown in close end to end relation, but there is no draft connection directly between the two car bodies, all draft between and '7, the equalization connection between the the two carbodies,'both positive and negative, being transmitted exclusively at low level through the truck and the longitudinal draft/connections to and between the car bodies. f

In the figures referred -to the car A is. shown as having the entrance and exit vestibule .55 at one end. The adjacent end of oar B isv not pro-l vided with such a vestibule but only with the small entrance passage 56 which, corresponding to the passage 56a in car A, lies between the two supporting columnar structures I6. Thus, only I one end of each car need have an entrance vestibule, and the total iioor space of eachcar may therefore be more eiiiciently utilized for passenger or other purposes. As shown in the drawings the two adjacent car ends are slmplyjuxtaposed, intervening bellows or other-similar elements 51 and 58 and a iioating floor panel 59 closing the intervening gaps.

The several relative motions between the truck or wheel and axle unit and the vcar body will now be explained. Relative longitudinal motion is allowed by the action j ust above explained, being allowed by the relative longitudinal movement, longitudinal tipping, of the columnar structures which suspend and control the car body at the described relatively high level. The

relative longitudinal movement is allowed by the described longitudinal movement of the supporting structure, and is controlled and restricted solely by the low level draftconnection.

Relative lateral movement between the car body and the truck or wheel and axle unit takes place in the form of lateral oscillation or swinging of thecar body about the defined high level longitudinal axis. Whenever the car body is subjected to any lateral thrust, as for instance byh lateral unevenness of trackage, or by centrifugal forces engendered in rounding a curve, those lateral thrusts and forces may be considered as-a single lateral force acting upon the center o1' gravity or mass of the car body. Due to the fact that the car body is restrained against lateral motion at the high level L, and due also to the fact that the lateral restraining means is articulate (such as is represented by the ball joints at the upper ends of the vertically yielding and vertically movable controlling columns) the body is restrained from translative lateral movement at that level and consequently must move laterally about a longitudinal axis disposed substantially at that level. Thus. when subjectv to any lateral thrusts the body swings about a. high longitudinal center of oscillation located substan tially at the position denoted C. O. in the drawr ings, Fig. 5 illustrates a typical relative position taken by the body when subjected to a lateral thrust from the left in that figure. The left hand columnar structurel 6 is depressed while the right hand structure rises. In the-form of the invention shown in Figs. 4 and 5, the two columnar structures may, although not necessarily, rise and fall equally, and the two sets of springs .34 may remain under vsubstantially eoual compression, due to'the equalizing action of lever 36. And the dash-pots act to retard and damp the swinging oscillation to whatever degree may be desired.

In the form of the invention shown in Figs. 6

two laterally spaced supporting and controlling structures may be applied to those structuresv through the medium of the dash-pot controlslinstead of through the medium of the suspension` springs. Here the equalization-isI shown as being 75.

, orice 66 of a size suitable to the degree of reeilected by-a iiuid conduit 65 which is connected betweim the lower ends of the opposite dash-pot cylinders I0, the conduit containing a restricted tardation andjidampig desired. And in this form of the invention the lower ends of the supporting springs 34a, instead of being mounted on the equalizing lever 36, are mounted directly upon the axle frame I5.

In this form of the invention oscillative swinging about the highcenter of oscillation is caused and controlled by the same 'suspensions and lateral controls as before described; but in this case the oscillative swinging is allowed by the elastic compressions and' extensions of the suspension springs 34a, instead of by the bodily yielding vertical movement of the spring columns which may take place in the form previously described.

So far as concerns the motion of lateral oscil lation of the car body, the centers of the ball joints I8, I9 may be looked at as the points at which the vertically yielding and articulate suspension and controlling cblumns are connected with a rigid portion of the car body. If the body and truck are travelling a straight-away track the linkarms 20 remain rigidly in substantially the relative positions that are 'shown in Fig. 2. When the car body swings to such a position as illustrated in Figs. 5 and 7, the linear distance between the centers of .the articulate joints I8, IQ increases slightly, and the angle of convergence of the laterally opposed arms of a pair consequently decreases slightly. But, in whatever relative position the arms are put by that action, they still remain in full effect rigid parts of the body insofar as translative lateral movement ofthe body at that level is concerned.r And the same is true when the relative. positions of the arms are changed by swivelling action of the car body with relation to the truck lwhen rounding a curve. Lateral forces cannot move the body translatively at the level L, regardless of th: relative positions of arms 20. except to the slight extent permitted 4l.

The swivelling action of the various pr-rts in rounding a curve is illustrated in Fig. 3. Due to the orientation, in plan; of the two sets of link arms 20, a virtual swivelling 'center `ls set up for both car bodies A and B at the common center indicated by the numeral 30 in Fig. 2, when the car bodies and truck are in their normal straightaway position. In rounding a curve, when the car bodies A and B take such a relative angular position as shown in Fig. 3, the arms 2i)v swing in horizontal planes to the typical positions shown in that figure. For an average or normal maximum angularity of the car bodies," or normal minimum curve radius, the virtual centers of swivelling of'ime two. car bodies remain very closely coincidenthaving a maximum displacement to such points as are indicated at 30a in Fig. 3. p

Again it Imay be noted that into whatever relative angular vpositions thearms 20 are moved by swivelling motions of the car bodies, the arms in that posiiton are rigid with respect to the car bodies so far as relative movement by any lateral forces are concerned. And consequently columnar structures which suspend and control motions of car body still exert'their lateral re- `straints on 'the car body at the specified high level, actingrthrough the effectively rigidarms 30. It may also be noted that when there is a change in the angular relationship of the two by the lateral elasticity of pads l Larms V2li oi' a pair, as for instance shown in Fig.

3 the car body also moves slightly longitudinally with reference to the truck or the wheel axle unit. Thus, in Fig. 3. the arms ofl each pair have moved to a greater angle o! convergence than in the normal position of Fig. 2. The point indicated diagrammatically at 'I0 in Fig. 3 is a fixed point with relation to the car body B. The transverse line indicated diagrammatically at II in that figure is a iixed line in relation to the upper ends of the supporting columnar structures I6. In moving to the relative positions shown in Fig. 3 the distance of point 'Ili'rom vline 1I, measured along center line C. L. of the body, is somewhat less than it is when the car bodies and truck are in their normal straight-away positions. This slight relative longitudinal movement between the car body and the upper ends of the suspension system is allowed for mainly or quite wh'olly by the longitudinal tilting of the suspension system which has been before described as allowing relative longitudinal movement between the car body and the truck or wheel and axle unit. The draft connection may allow' some slight relative longitudinal movement between the car body and the ,truck or wheel and axle unit, but by the very nature of its duties its longitudinal yielding is comparatively stii. Relative longitudinal movement between the car body and the truck or wheel and 'axle unit, from 301. whatever cause, is therefore taken' c'sre oi by the longitudinaltilting yieldabilityof the up?" ball joints I8, I9 of a pair.

I claim:

1. In combination with a car body and awheel 4c' \f unit located beneath the-body; `a suspension'sys'- tern for the body on the wheel unit, comprising standing columnar supportingiand coutrolstruc-V` tures, tilting about the axis of the wheel Vand axle unit and about thev horizontal transverse highv axis which extends between the `laterally opposed,

two body supporting elements supported at their` j lower ends on the wheel unit, spaced from 'each I other laterally at vopposite sides of the vertical'l longitudinal central'y plane of the body, l,extendtially the center of gravity of the body, and each i'4 ing up into the body to a level above substanf being independently vertically yielding; inde` pendent supporting connections between thepper ends of each of the supporting elements and the body, Veach of Awhich connections includes a body supporting arm articulated at one end to the element and at fth other end to the body, one of said articulations being universally swivelling and locatedfat said-defined level, and each arm being swingable about its last mentionedarticulation in a direction havings longitudinal component; and means restricting translative f lateral movement of the last mentioned articulation of each arm` relative to the wheel unit. 2. In combination with a carbody and a wheel lunit located beneath the body; a'suspension system for the body on the wheel unit, comprising two body supporting elements supported at their lower ends on the wheel units'paced from eachv other laterally at opposite sides of the vertical. longitudinal central plane o f the body, extendingv one of said articulations being universally swivelling and located at said defined level, and each arm being swingable about its last mentioned articulation in a direction having a longitudinal component; and means restricting translative lateral movement of the last mentioned articulation 0f each arm relative to the wheel unit.

3. In combination with a car body and a wheel unit located beneath the body; a suspension system for the body on the wheel unit, comprising two body supporting columnar structures supported at their lower ends on the wheel unit, extending up into the body to a level above substantially the center of gravity of the body and laterally spaced from each other at opposite sides.

oi.' the vertical longitudinal central plane of the body, each of said columnar structures being independently vertically yielding, restricted against lateral movement with relation to the wheel unit and including a vertically elastic supporting element; and independent supporting connections between the upper ends of each of the columnar structures and the body, each of which connections includes a body supporting arm articulated at one end to the columnar structure and at the other end to the body, one of said articulations being universally swivelling and located at said dened level, and each arm being swingable about its last mentioned articulation in a direction having a-longitudinal component.

4. In combination with a car body and a wheel unit located beneath the body; a suspension system forthe body on the wheel unit, comprising; a frame mounted on the wheel u'nit, two upwardly extending guide members mounted on the frame laterally spaced from each other at opposite sides of the vertical central longitudinal plane of the body, vertically movable members guided one by each of the guide members, universal pivotal joints one at the upper end of each vertically movable member, said joints located at a level above substantially the center of gravity of the body, links connected each at one end with one of said joints and at the other end pivotally connected with the body to swing only horizontally relative thereto, and a vertically elastic body supporting spring associated with each vertically movable member to support it.

5. In combination with a vehicle body and a wheel unit beneath the body, a suspension system for the body on the wheel unit, comprising; a pair of vertically yielding body supporting members, spaced laterally from each other at opposite sides of the vertical central longitudinal plane of the body, mounted on the wheel unit below and reaching up in the body to a level above substantially the center of gravity of the body, and a pair of substantially horizontally disposed non-parallel arms each pivotally connected at one end to the upper end of one of said members and pivotally connected at the other end to the body, one of said pivotal connections for each arm restricting its motion to swinging in a substantially horizontal plane.

6. In combination with a vehicle body and a wheel unit beneath the body; a suspension system for the body on the wheel unit, comprising two longitudinally spaced pairs of vertically yielding body supporting members, the members of each pair being spaced laterally from each other at opposite sides of the vertical longitudinal central plane of the body. mounted on the Wheel unit below and reaching up in the -body to a level above substantially the center of gravity of the body, four horizontally disposed arms each pivottem for the body on the wheel unit, comprising `two body supporting elements supported at their lower ends on the wheel unit, spaced from each other laterally at opposite sides of the vertical longitudinal central plane of the body, extending up into the body to a level above substantially the center of gravity of the body, and each said element being independently vertically yielding; independent supporting connections between the upper ends of each of the supporting elements and the bodyfeach of which connections includes a body supporting arm articulated at one end to the element and at the other end to the body, one of said articulations being universally swivelling'and located at said defined level, and each arm being swingable about its last mentioned articulation in a direction having a longitudinal component; means restricting translative lateral movement of the last mentioned articulation of each arm relative to the wheel unit; and longitudinal draft connection between the wheel unit and the body comprising a connector located substantially in the vertical longitudinal central plane of the body and exclusively at the substantial level of the wheel unit and below the rst deiinedlevel, and having flexibility vertically, laterally and torsionally about a longitudinal axis. v

8. In combination with a car body and a wheel unit located beneath the body; a suspension system for the body on the wheel unit, comprisingtwo body supporting columnar structures supported at their lower ends on the wheel unit, extending up into the body to a level above substantially the center of gravity of the body and laterally spaced from each other at opposite sides of the vertical longitudinal central plane of the body, each of said columnar structures being independently vertically yielding, restricted against lateral movement with relation to the wheel unit and including a vertically elastic supporting element; independent supporting connections between the upper ends of each of the columnar structures and the body, each of which connections includes a body supporting arm articulated at one end to the columnar structure and at the other end to the body, one of said articulations being universally swivelling and locatedat said deiined level, and each arm being swingable about its last mentioned articulation in a direction having a longitudinal component; and longitudinal draft connection between the wheel unit and the body comprising a connector located substantially in the vertical longitudinal central plane of the body and exclusively at the substantial level of the wheel unit and below the iirst defined level, and having iiexibility vertically, laterally and torsionally about a longitudinal axis.

9. In combination with a car body and a wheel unit located beneath the body; a suspension system for the body on the wheel unit, comprising two body supporting and controlling elements supported at their lower ends on the wheel unit, spaced laterally from each other at opposite sides oi' the vertical longitudinal central plane of the body, extending upwardly from the wheel unit and each independently supportingly connected with the body at their upper ends, said elements being oppositely yieldable in a longitudinal direct'ion to permitswivelling of the body in a horizontalplane relative to the wheel and axle unit, and said elements being oppositely vertically yielding, and said suspension system also includingilexible means acting on the body substantiallyy exclusively at a level above substantially the center ofA gravity of the body to restrain translative lateral movement of the body at that level withrelation to the wheel unit and to allow lateral movement of the body at all other levels, said suspension system being yielding longitudinally, andV longitudinal draft connection between the wheel unit and the body comprising a connector located substantially in the vertical longitudinal central plane of the body and exclusively at substantially the level of the wheel unit and below saidlevel of lateral control, and having flexibility vertically, laterally and torsionally about a longitudinal axis so as to allow vertical, lateral swinging, and horizontal swivelling movements relatively between the body andthe Wheel unit.

Y 10. In combination with a car body and a wheel unit located beneath the body; a suspension system tor the body on the wheel unit, comprising two body supporting columnar structures supported at their lower ends on the wheel unit, extending up into the body to a level above substantially the center oi' gravity of the body and laterally spaced from each other at opposite sides of the vertical longitudinal central plane of the body, each said columnar structure including a vertically telescopng pair of tubular members resistant to lateral displacement, and a vertically elastic spring within the tubular members; and independent supporting connections between the upper ends vof each of the columnar structures and the body, each of which connections includes a body supporting arm articulated at one end to the columnar structure and at the other end to the body, one of said articulations being universally swivelling and located at said defined level, and each arm being swingable about its last mentioned articulation in a direction having a longitudinal component.

l1. In combination with a car body and a wheel unit beneath the body; a suspension system for the body on the wheel unit, comprising two body supporting and controlling` elements supported at their lower ends on the wheel unit, spaced laterally from each other at opposite sides of the vertical longitudinal central plane of thebody, extending upwardly into the body to a level above substantially the center of gravity of the body, each of said elements being independently elastically vertically yielding and each independently supportingly connected with a rigid part of the vertical movements of said two elements are balbody at said level, and said elements being oppositely yieldable in a longitudinal direction to permit swivelling o1' the body in a horizontal plane relative lto the wheel unit; and longitudinal draft connection between the wheel unit and the body 5 comprising a connector located substantially in the vertical longitudinal central plane of the body and exclusively at the substantial level of the wheel unit and below the first defined level, and having flexibility vertically, laterally and torsion- 1 ally about a longitudinal axis so as to allow vertical, lateral swinging, and horizontal swivelling movements relatively between the body and the wheel unit.

12. In combination with a car body, a truck 1 comprising two longitudinally spaced wheel units, a frame mounted on each wheel unit to swing thereon in a vertical plane longitudinal of the body, a vertically flexible and laterally rigid connection between the two frames; a vertically elas- 2 tic supporting unit mounted on each of the frames, extending upwardly therefrom and ilexibly and supportingly connected at its upper end to the body at a level above the substantial center of gravity of the body, said flexible support- 2 ing connection allowing angular movement between the supporting unit and the body in a longitudinal vertical plane; and longitudinal Idraft connection between at least one of the frames and the body comprising a longitudinal connector 30- located substantially in the plane of the wheel units and below said flexible supporting connection and having vertical flexibility.

13. In combination with a car body and a wheel unit beneath the body; a suspension system forthe body on the wheel una, comprising two body supporting and controlling elements supported at their lower ends pn the wheel unit, spaced laterally from each other at opposite sides of the vertical longitudinal central plane of the body, 4 extending upwardly into the body to a level above substantially the center of gravity oi' the body, each of said elements being elastically vertically yielding and each independently supportingly connected with a rigid part of the Ibody at saidA level, and said elements being oppositely yield-v able in a. longitudinal direction to permit swivelling o! the body in a horizontal plane relative to the wheel unit; equalizing means whereby the anced against each other; and longitudinal draft 5 connection between the wheel unit and the body comprising a connector located substantially in the vertical longitudinal central plane of the body and exclusively at the substantial level of the wheel unit and below the first defined level, and having flexibility vertically, laterally and torsionally about a longitudinal axis so as to allow vertical, lateral swinging, and horizontal swivelling movements relatively between the body and the 6 wheel unit.

WILLIAM E. VAN DORN. 

